Abstract

VHE gamma-ray source HESSJ1943+213 was discovered by the HESS Cherenkov telescope array during the Galactic Plane survey. In the TeV range the source is characterized by a soft spectrum, $┬ąGamma_{VHE} =3.1$, and appears steady. Despite the established X-ray and radio counterparts, the nature of the object remained uncertain, although the HESS Collaboration favored the ``extreme BL Lacertae'' classification. HESSJ1943+213 was not detected during the first 21 months of the Fermi-LAT operation. Here we report on the analysis of the most recent accumulation of the LAT data at the position of the TeV emitter; the source is still not detected in the GeV range, with the corresponding flux upper limits significantly below the VHE flux level. We also present new Suzaku data for the object obtained in 2011 November.

The source is clearly detected with the XIS (0.5-10 keV) and PIN (15-25 keV) instruments at the same flux level as previously with Chandra and Swift satellites. The X-ray spectrum of HESSJ1943+213 is well represented by a single power-law with photon index $┬ąGamma_X = 2.0$, excess absorption, and no signatures for spectral curvature/cut-off within the whole accessible 0.5-25 keV range. We complement the multiwavelength data with infrared fluxes newly provided at the position of the source by the Wide-field Infrared Survey Explorer.

We discuss how the updated broad-band spectrum of the source with much improved temporal and spectral characteristics in the infrared, X-ray and GeV ranges may help us to understand the enigmatic nature of HESSJ1943+213.